Project Summary Across HIV and sexually transmitted infections (STIs), the real-time understanding of transmission networks of recently infected individuals is vital for the rapid diagnosis, treatment, and prevention of new cases, and in providing insight into how the disease is transmitted, which populations are at highest risk, and who should be targeted for intervention. One of the most effective and widely implemented methods for understanding and intervening upon transmission networks is Partner Services - or interviewing a person newly diagnosed with HIV in order to identify any potentially exposed partners and notify, test, and if necessary, connect those partners to care. Backed by the Centers for Disease Control and Prevention as an evidence-based intervention for those newly diagnosed with HIV or STIs, Partner Services is a foundational public health response shown to be highly effective at slowing the spread of HIV. Unfortunately, the implementation of Partner Services by public health departments is often a challenge. Health departments have limited financial and logistical resources, disease investigators balance competing priorities of building relational trust while simultaneously recording detailed data, and by its nature, sexual and drug network data is complicated and poses enormous methodological challenges during data capture, processing, and storage. In response to similar difficulties in the collection of social network research data, our team has built a free open-source and NIH-funded software suite for researchers, called Network Canvas. By building on the strengths of our existing software tool, we next hope to build a free and open-source software tool that will simplify and modernize disease investigation for public health officials conducting Partner Services, and this proposed R34 will support the necessary formative work. In particular, we will characterize the needs of public health departments conducting Partner Services and develop a detailed specification of the software reconfiguration necessary to meet these needs. We will also develop and implement a pilot of the software within Partner Services at the Chicago Department of Public Health in order to demonstrate feasibility, acceptability, and gather preliminary evidence of efficacy. We will conduct this work guided by Active Implementation Frameworks which utilize a staged-approach and strong engagement with local (e.g., Chicago Department of Public Health) and national stakeholders (e.g., National Coalition of STD Directors) to explore, install, and implement a software pilot into Partner Services. This project will provide the formative work necessary to inform the development of a future full-scale, R01- level multi-site stepped wedge implementation trial in which we will evaluate the effectiveness of Network Canvas in improving outcomes for Partner Services. Finally, this R34 is in the line with PA-18-780 to develop and test a novel intervention to improve HIV prevention, care, and program implementation (Clinical Trial Optional).